Circuit breakers are the central part of air-insulated (AIS) and gas-insulated (GIS) switchgear. High-voltage circuit breakers are mechanical switching devices which connect and break current circuits (operating currents and fault currents) and carry the nominal current in closed position.As a world market leader, Siemens takes the responsibility to provide circuit breakers which meet the environmental, technological and economic conditions in the various countries worldwide.

▪ Voltage range from 72.5 kV up to 800 kV▪ More than 135,000 circuit breakers delivered▪ More than 150 countries delivered

Modular Design

Few basic components leading to a high diversity of types

Siemens high-voltage circuit breakers, regardless of type or voltage range, are designed in a well proven modular platform concept. This leads to a high diversity of circuit breaker types and to high flexibility with regard to various applications according to our customers’ requirements.

The main components, such as

operating mechanism,

control system,

base frame,

kinematic chain and

insulator designs

are identical and based on decades of manufacturing and operating experience. Our GIS switchgear range also includes the same interrupter units, operating mechanisms and control elements. By applying this proven modular design not only at our lead factory in Germany, but also within our global manufacturing network, we are able to fulfill the highest expectations regarding availability and reliability at eminently competitive prices.

Quenching Principles

Our complete 3AP family up to 800 kV and above relies on our arc-quenching principles, either the self-compression or the dynamic self-compression principle using the thermal energy of the arc. Siemens patented this method for arc quenching in 1973 and has continued to develop the technology of the self-compression interrupter unit. In short-circuit breaking operations the actuating energy required is reduced to the energy needed for mechanical contact movement.

If you have any questions concerning mode of operation or other details please do not hesitate to contact us or download information material on our circuit breakers.

Drive Systems

Stored-energy spring mechanism

The operating mechanism is a central part of high-voltage circuit breakers. The drive concept of the 3AP circuit breaker family is based on the patented stored-energy spring principle and is identical on all types. The use of such an operating mechanism for voltage ranges of up to 800 kV became appropriate as a result of the development of a self-compression interrupter unit that requires minimal actuating energy. The compact design of this operating mechanism makes it possible to place the stored-energy spring mechanism within the control cubicle in a compact housing.

The mechanism types differ in terms of the number, size and arrangement of the opening and closing springs. Both the closing and opening springs are located inside the operating mechanism, thereby achieving a simple and sturdy device. This design minimizes the number of required moving parts. The use of roller bearings and of the maintenance-free charging mechanism is a prerequisite for reliable operation over decades. Proven design principles such as vibration-isolated latches and load-free isolation of the charging mechanism were retained.

Fail-safe, economical and persistent due to uncomplicated and robust construction with few moving parts

Controllable switching state at all times

Easy access to springs as they are not integrated in SF6 compartments

Maintenance-free for 25 years or 6,000 operation cycles

Low environmental impact compared to former drive systems

Stored-energy spring mechanism

Electrohydraulic operating mechanism

The electrohydraulic operating mechanism has been used in 3AT and 3AQ circuit breakers for more than 20 years. Even the highest switching voltages are safely brought under control in the shortest possible time and also the most difficult switching tasks can be mastered.

Advantages of the electrohydraulic operating mechanism:

High operating energy for the highest switching performance in the shortest possible time

Contact positions are reliably maintained even if the auxiliary power supply fails

Multiple reclosure possible without the need for recharging

Constant self-monitoring

Checking of energy reserves at any time

Low-maintenance, economical and long service life

Meets stringent environmental protection requirements

Electrohydraulic operating mechanism

Composite Insulators

Field of application:▪ Bushings for transformers and other devices▪ Grading capacitors▪ Voltage and current transformers▪ Cable connections▪ Surge arresters▪ Circuit breakers

Testfields and Type Tests

Test field at Berlin factory accredited to EN 45001 and part of independent PEHLA organization

The foundation of quality for Siemens high-voltage circuit breakers begins right in the development of a new product. Switching performance, high voltage stability and performance under normal mechanical loads (wind and short circuits) as well as seismic conditions are simulated and optimized in the outline design phase using computer-aided calculations. The use of parts and assembly units in a large number of breaker types such as live tank, dead tank, as well as GIS leads to a high volume standardization of the main components. Steady and regular amounts of produced units form a continuous production process and ensure the highest standards. Statistical quality control is based on large numbers produced, and hence, a higher validity is achieved. All 3AP circuit breakers are earthquake-proof up to 0.5 g.

Low temperature test of a 3AP1 DTC 145 kV

All our circuit breakers are completely type-tested in accordance with latest IEC and ANSI standards before their market launch. In our Berlin factory, we have one of the most modern testing laboratories available which are accredited to EN 45001 and part of the European network of the independent testing organization, PEHLA. All required facilities are available: ▪ Physics laboratory▪ High-voltage testing laboratory▪ High-power testing laboratory▪ Mechanical testing laboratory▪ Temperature rise testing laboratoryOther testing laboratories that we work together with are KEMA, CESI, IPH and FGH, which are also part of the European network of independent testing organizations.

Routine Tests

Routine test of a 3AP1 DT 245 kV

Important components are subjected to complete pre-acceptance testing before assembly. The routine test is performed on the assembled circuit breaker. The specification requirements are automatically imported into the computer-aided routine test plan during order processing. This makes sure that fulfillment of every customer requirement is checked before delivery.

Routine testing is performed in accordance with IEC or ANSI and encompasses the following points at least: ▪ 100 mechanical operations▪ Closing and opening times▪ Release and motor currents▪ Gas monitoring▪ Testing of control circuits in accordance with the circuit diagram▪ Voltage drop of the main conducting path▪ High-voltage testing▪ 2 kV testing of auxiliary circuits

Gas Leakage

Gas leakage testing area

IEC specifies an annual maximum SF6 leakage rate of 0.5 % or 1 %. Experience from several high and low temperature tests and decades of operational experience show that the leakage rate of Siemens circuit breakers is beloweven 0.1 % per year.

Installation and Commissioning

We provide installation and commissioning on request. We are available 24 hours worldwide.

USA, Jackson

3AP1 Dead Tank CB 38 kV up to 245 kV

Description

Special technical features of dead-tank design. The distinguishing feature of dead-tank technology is that the interrupter chamber is accommodated in an earthed metal housing. With this arrangement the SF6 gas filling insulates the high voltage live parts of the contact assembly from the housing. Outdoor bushings connect the interrupter chamber with the high-voltage terminals.